This paper discusses the dependence of current sociological efforts towards explaining the rise of western rationalism on Christian replacement theology. Replacement theology is the view that Jesus redeeming sacrifice reported in the Gospels superseded and replaced Judaism because it made universal the access to divine grace, which had before been restricted to an ascriptive chosen people. I argue that this theological thesis lies at the root of Webers view that the pariah condition peculiar to the Jewish people made the Jews - unlike Pauls missionary work - unable to diffuse the rational conduct of life which had been established through the (Hebrew) prophetic doctrine of a universal God.